But under the 1998 Federal Vacancies Reform Act, Zients' appointment was limited to 210 days, which means his status as acting director expired last September. At that time, he reverted back to his original role as deputy director for management. After that, Zients even stopped signing official OMB communications under the title "acting director."

However, all that changed on March 4 when Obama nominated Sylvia Mathews Burwell, president of the Walmart Foundation, to permanently head the office. The vacancies law contains a "spring-back" provision, which allows a former acting official to resume the duties of the office after the President makes an official nomination.

An OMB spokeswoman said Zients' continued to lead OMB from his deputy director for management role even after his acting appointment expired. His authorities and responsibilities did not change, the spokeswoman said.